The present invention relates to the art of braiding machines and, more particularly, to improvements in a strand carrier for carrying and controllably releasing a strand in a braiding machine.
Braiding machines are of course well known and are used, for example, to braid metallic wire into electrical or electronic cable as a protective armor, or into hydraulic hose and cordage as a load bearing structure, or into metallic or non-metallic rope. The present invention relates to improvements in a strand carrier for such machines and, in particular, to a strand carrier of the type having coaxial base, bobbin, strand guide and tension head components, such as the carrier illustrated and described in my U.S. Pat. No. 4,719,838, the disclosure of which is incorporated herein by reference.
In a carrier of the foregoing character, the tension head is comprised of an axially fixed member and an axially movable member spring biased away from the fixed member. Each of the head members has an arrangement of strand pulleys which guide the strand between the member such that tension applied to the strand urges the axially movable member toward the axially fixed member against the bias of the springs between the members. Further in connection with such a tension head, a clutch plate is interposed between the movable member and bobbin and is biased toward the bobbin by clutch spring units between the clutch plate and the fixed member of the tension head. When the tension applied to the strand urges the axially movable member toward the axially fixed member, the clutch spring units are displaced by the movable member to release the clutch plate from the bobbin freeing the latter to rotate relative to the strand guide and tension head allowing strand to play from the bobbin.
In the tension head disclosed in my aforementioned patent, the tension controlling springs are captured between the fixed and movable members by having their opposite ends received in corresponding spring pockets in the two members. Further, the clutch spring units include spring supporting members secured to the clutch plate and extending through openings therefor in the movable member toward the fixed member, and the clutch springs are axially captured between the spring supports and fixed member of the head by having their opposite ends received in corresponding spring pockets in the supports and fixed member. The fixed and movable head members with the tension controlling springs and clutch springs compressed therebetween are mounted on a sleeve member together with the clutch plate to provide the tension head. The clutch plate is axially retained at one end of the sleeve by a split ring, and the fixed member is pinned to the sleeve adjacent the opposite end thereof to maintain the component parts against axial separation. The bobbin and tension head are mounted on the shaft portion of the base together with the strand guide holder, and these component parts are secured to the shaft against axial separation by an end cap member bolted to the shaft and engaging the axially outer end of the fixed member of the tension head assembly.
To disassemble the major parts of the carrier, the end cap is removed to free the tension head, bobbin and strand guide holder for removal from the shaft. Disassembly of the tension head for repair or replacement of the component parts thereof requires removal of the pins engaging the fixed member with the sleeve against axial separation therefrom. Removal of the latter pins releases the movable member for axial separation from the sleeve, and this operation is both cumbersome and hazardous to the person disassembling the tension head as well as to other persons or objects in the vicinity of the disassembly work. In this respect, tension controlling springs generally have an uncompressed length of twenty or more inches, a compressed length of about four inches, and a force when compressed of from ten to forth pounds. Accordingly, when the movable head member is released for axial separation from the supporting sleeve, extreme care must be exercised to avoid unintended release or lateral displacement of the movable member relative to the spring axes during decompression of the springs. Otherwise, the head member and/or springs become projectiles which can seriously injure the worker or other persons in the vicinity thereof. Moreover, the head member and/or springs can impact with other equipment in the area damaging the latter as well as the head member and springs. Even though a worker may be able to hold onto the movable head member, the spring soften become dislodged prior to full decompression thereof and are propelled by their own resiliency from their positions between the fixed and movable head member.
Further problems are incurred in connection with assembling or reassembling the components parts of the tension head. In this respect, it will be appreciated that it is extremely difficult to maintain proper alignment between a plurality of compression springs having a length of twenty or more inches while the springs are displaced by moving the fixed member of the tension head assembly towards the movable member and to the assembled relationship therewith in which the compression springs have been compressed to a length of about four inches. Again, a hazardous situation is presented in that the compression springs can become dislodged from between the two members of the tension head, thus exposing the worker to potential injury. Thus, the assembly operation too is both tedious and potentially hazardous. Moreover , the potential for injury adds to the anxiety of the worker during both assembly and disassembly operations. Adding further to such tediousness and anxiety is the fact that the insertion and removal of the pins holding the fixed member to the sleeve component of the tension head requires holding the fixed member against the spring force with one hand while manipulating the pins with the other hand such as through the use of pliers, and working with the latter in the area occupied by the hand holding the fixed member against the spring force.
In addition to the foregoing problems, even if just one of the tension controlling springs or one of the clutch springs needs to be replaced, the foregoing disassembly and reassembly operations are necessary to do so.